Contacting tray with rotatable valves



Aug- 1964 M. c. JONES ETAL CONTACTING TRAY WITH ROTATABLE VALVES 2 Sheets-Sheet 1 Filed Sept. 27, 1961 FIG.

FIG. 2

FIG.

INVENTORS MICHAEL C. JONES WOLDEMAR TEDDER THEIR ATTORNEY g 4, 1964 M. c. JbNEs ETAL 3,143,582

CONTACTING TRAY WITH ROTATABLE VALVES Filed Sept. 27, 1961 2 Sheets-Sheet 2 IO I3 I ll L] u 2 I ll FIG. 5

FIG. 7

INVENTORS'.

MICHAEL C. JONES WOLDEMAR TEDDER BY a THEIR ATTORNEY United States Patent CONTACTMG TRAY WITH RUTATABLE VALVES Michael C. Jones, ()akland, Calif., and Waldemar Tedder,

The Hague, Netherlands, assignors to Shell Oil Cornpany, New York, N.Y., a corporation of Delaware Filed Sept. 27, 1961, Ser. No. 141,051 iaims priority, appiication Netherlands Get. 3, 1960 5 Claims. (Cl. 261-114) The invention relates to contacting trays, sometimes called bubble trays, suitable for installation in a contacting column for eifecting exchange between ascending gas and descending liquid, e.g., for distillation, absorption, or the like. The term gas is used herein to include vapor.

More particularly, the invention is concerned with contacting trays having variable gas passages, wherein each gas passage is controlled by a valve body which is vertically movable, an upper part being positioned above the passage through the tray and supported in the lower position thereof by the upper tray surface, wherein each valve body had a guide member extending downward through the tray opening and provided at the bottom with a stop impinging on the bottom side of the tray when the valve is lifted.

Trays of this type are known, for instance, from the Belgian patent specification 588,502.

When in operation the gas passages and/or the valves of such trays tend to foul somewhat on the edges owing to the deposit of constituents of the media being treated or of impurities present therein. The openings or valves may also be slightly affected in some other Way, for instance, by media which attacks the metal. It was found that the valve may stick due to these tendencies. Sticking adversely affects the operation of the tray, since the valve opening is no longer able to adapt itself to the working conditions, such as the rate of gas fiow.

The general object of the invention is to obviate the above-mentioned drawback by causing the valve to rotate during use.

Another object is to provide an improved valve of the type described above having blades or louvers arranged to be engaged by the ascending gas in a manner to cause the valve to rotate about its vertical center line coincidental with the vertical movement thereof.

In summary, the valve body comprises a top plate which substantially closes the opening in the tray (but which is not necessarily imperforate) and means, such as a plurality of inclined blades formed in the top plate above the tray and/ or in the sides of the dependent structure which slides through the tray opening, arranged to cause ascending gas to exert a torque on the valve as the gas escapes adjacently to the blades above the tray level.

This construction not only permits the valves to be lifted to a greater or lesser extent in accordance with the tray loading, i.e., the pressure difierential across the tray as determined by the gas-flow rate, but causes a slight rotation of the valve at least during the vertical movement. The edges of the tray opening and of the valve guide are thereby scraped clean, and at the same time the risk of adherence of the valve to the tray at points of contact is minimized, since owing to the rotation different points are brought into contact with each other when the valve is lifted again.

In one embodiment of the invention the said means for causing rotation are blades formed in the top plate of "ice the valve, which is formed with radial incisions and the resultant sectors of the plate are bent out of the plane of the plate, a plurality of blades being thus formed which are oriented to enable the rising gas to impart a rotating movement to the valve during operation.

In another embodiment the valve is made of one piece of sheet metal which comprises a central, usually substantially imperforate portion constituting the valve top plate, and a plurality of strips which are bent downwardly at the periphery of the plate to form guide members. In this embodiment the said strips are inclined to the radius from the vertical center line of the valve to form blades (being twisted, if desired), and the gas exerts a torque as it flows laterally between the blades above the tray surface.

In still another embodiment the valve has a cage-like structure including a top plate and a generally cylindrical wall extending downwardly therefrom through the tray opening, the top plate having an outward projection or lip for engagement with the top tray surface, the said wall being provided with a plurality of inwardly directed lips and passages, e.g., formed by making suitable incisions in the wall and bending the metal inward, so that the lips form the blades, which act as described in the preceding paragraph.

The invention will be further described with reference to the accompanying drawings forming a part of this specification and showing three specific embodiments by way of illustration, wherein:

FIGURE 1 is a vertical sectional view through a part of a tray fitted with a valve according to the invention, the valve being shown in elevation at an intermediate height;

FIGURE 2 is a plan view of the valve according to FIGURE 1;

FIGURE 3 is a plan view of a blank suitable for forming a valve according to a second embodiment, prior to bending the strips;

FIGURE 4 is a plan view of the valve resulting from the blank of FIGURE 3;

FIGURE 5 is a vertical sectional view through a part of a tray fitted with the valve of the second embodiment,

FIGURE 6 is a vertical sectional view through a part of a tray fitted with a valve according to a third embodiment;

FIGURE 7 is a fragmentary sectional view taken on the line 7-7 of FIGURE 6; and

FIGURE 8 shows a part of the valve according to FIGURE 6 modified to provide a minimum permanent passage.

Referring to FIGURES 1 and '2, the valve comprises a top plate 1 having a generally circular outline of diameter greater than that of a circular opening 2 formed in a tray 3 so as to substantially close the opening and rest on the tray when in its lowermost position. The valve has a plurality of guides 4 distributed above the periphery of the top plate near the edge of the opening, each guide having a stop 5 at the lower end thereof for engagement with the underside of the tray. The guides may be formed integrally with the top plate by bending along lines spaced inwardly from the plate edge, suitable incisions being made first. However, the invention is not limited to such a construction of the guides; thus, guides made of wire may be used. The top plate has a plurality of radially or substantially radially oriented incisions 6 and 7 forming a number of sectors. These sectors are bent out of the through the tray with valves.

plane of the plate 1 to form blades 9. When in its lower position only the'edges of the blades 9 engage the tray surface. The valve is installed by deforming the guides, which are advantageously resilient.

In operation the valve rises to a greater or lesser height in accordance with the tray loading. During its upward movement it also rotates because the ascending gas is deflected by the blades 9, thereby imparting a torque to the valve about its central vertical axis. When the valve is fully raised most of the gas escapes laterally between the guides and engagement of the stops with the tray usually impedes further rotation. The edges of the opening 3 are scraped clean by the guides each time rotation occurs. Further, each time the valve plate comes to rest on the tray it occupies a different orientation so that engagement is at new points of contact; this lessens the chance for sticking.

This embodiment has the additional advantage that the valve, when in its lowest position, does not completely seal the tray passage but engages it only at the bottom edges of the blades. This means that there is point contact between the valve and the tray which, as is known, substantially reduces the risk of the valves sticking. A second advantage is that it is possible for a small quantity of gas to penetrate into the liquid immediately above the valve, since a minimum valve opening is permanently maintained, the liquid immediately above the valve being thereby diluted with gas; this lowers the liquid density and makes it easier to initiate upward movement of the valve when the gas flow rate is increased.

The valve according to FIGURES 3-5 is made of a single piece of sheet metal, the blank being shown in FIGURE 3. The advantage of this construction is that the Waste of material is low. The valve blank consists of a central imperforate plate 10 having a plurality of radially extending strips 11, each having a lateral projection 12 to form a stop lug. The margins of the strips are defined in part by substantially radial incisions extending to the bend-lines, one of which is indicated at aa in FIGURE 3. When the guides are bent downward along these lines the narrow projections 13 of the plate can thereby rest on the upper tray surface.

It will be noted that the bend lines a-a are not perpendicular to the radius from the valve center to the midpoints of the bend lines; hence the guide strips form blades which, as appears from FIGURES 4 and 5, will be given a torque by the gas which rises through the central channel enclosed by these guides and escapes laterally above the tray surface. It is, of course, possible to twist these strips to attain the optimum angular positions. However, twisting is not usually necessary. It may be noted that it is not necessary to bend the stop lugs because these are brought into operative positions by bending on the indicated bend lines.

The valve of FIGURES 3-5 has the same additional advantages mentioned above for the first. The projections 13 contact the tray surface only at spaced points, and a minimum open area is permanently provided as shown at 14.

Of late valve trays have often been so designed as to leave a certain permanent minimum passage, i.e., the trays have a variable free space, the maximum value of which coincides with the state in which the valves have the maximum openings, namely when the stops on the guides engage the bottom surface of the tray. It has already been proposed to insure a minimum free passage by providing not all, but only some of the openings A minimum free passage can be insured with the valves described above.

In the embodiment according to FIGURES 6 and 7 each valve has a cage-like structure which includes a generally cylindrical wall 15 and a top closure plate 16, which projects radially beyond the former as indicated at 17 to form an edge for resting on the tray surface. In this embodiment the closure plate 16 is shown to be imperforate, although this is not restrictive of the invention. The edge 17 may, for example, as is shown in FIGURE 8 for the plate 16', be provided with circumferentially spaced downward projections 170, formed integrally therewith by forming incisions and bending down the corners at the incisions. Thereby contact of the valve with the upper tray surface at spaced points is attained.

The wall 15 is situated near the circular opening in the tray 3 to form a guide. It is provided with a plurality of vertical incisions in the upper part 18 above a continuous strip 11$, and the parts of the wall adjoining the incisions in a common circumferential direction are bent inwardly to form blades 20, alternating with gas passages 21. The continuous strip 19 fits into the tray to guide the valve when in its uppermost position.

The bottom of the cylindrical wall is provided with an out-turned flange 22 which forms a stop and may be bent outwardly after downward insertion through the tray opening. It is evident that this flange need not be continuous or integral with the cylindrical Wall.

If it is desired to maintain a minimum permanent opening, this may be provided by using the projections 17a of FIGURE 8 and/or by providing small openings the closure plate as indicated at 23 in FIGURE 8. 7

It should :be noted that trays provided with valves as described above may be expected to give an improvement" in contacting efliciency or performance owing to the vortex of the gas stream which issues with a vortical pattern. Because the valves themselves undergo only a slight rotational movement, and this principally while ascending, the principal effect of the blades during operation is to alter the direction of gas flow.

By a suitable selection of the direction of rotation of the valves placed at the edges, e.g., near the wall of the column, it is also possible to obtain a better distribution of liquid over the tray.

We claim as our invention:

1. A gas-liquid contacting apparatus comprising: a contacting tray adapted to be mounted horizon-tally within a contacting column to retain a body of liquid thereon and having a flow opening therethrough, and a valve mounted on said tray for vertical movement to control the passage through said opening by vertical movement due to upward gas flow, said valve comprising a valve plate situated above the tray engageable with the upper tray surface for support when the valve is in its lowest position, guide means extending vertically downwardly therefrom near the edge of said opening, the lower part of said guide means providing stops engageable with the under side of the tray to limit upward movement of the valve, said valve being rotatable about the vertical center line thereof, and spaced blades in a part of the valve which is situated above said contacting tray at least when the valve is in its uppermost position, said blade defining gas passages from which gas flowing is dispersed directly into said liquid, at least a portion of the blades including means which are inclined for rotating the valve coincidentally with vertical movement thereof.

2. Contacting apparatus as defined in claim 1 wherein the said means for rotating the valve comprises blades formed in said valve plate and providing therebetween passages extending therethrough and inclined to the plate surface.

3. Contacting apparatus as defined in claim 1 wherein the said means for rotating the valve comprises blades situated beneath said valve plate and situated above the tray level when the valve is in its uppermost position, said blades being situated near the edge of the said flow opening and enclosing a central gas-flow channel which is open at the bottom, said blades being spaced apart and inclined to the radius from said center line to define lateral gas passages for the discharge of gas laterally above the tray surface.

4. Contacting apparatus as defined in claim 1 wherein said valve consists of a single piece of sheet metal comprising a central, upper plate and a plurality of strips bent downwardly from said plate and forming collectively the said guide member, said strips being distributed about the periphery of the body and being inclined with respect to the radius from said center line to form blades to effect rotation of the valve due to the flow of gas upwards through the tray opening and between the said blades outwardly above the tray level.

5. Contacting apparatus as defined in claim 1 wherein said valve is cage-shaped and comprises a generally cylindrical outer wall constituting the said guide member and enclosing a central gas-flow channel which is open at the bottom, and atop closure plate, said plate having a lateral projection engageable with the top of the tray, said outer wall being provided with incisions and being shaped to provide blades inclined to the radius from said center line and intervening passages extending later-ally between said blades to eflect rotation of the valve due to the flow of gas upwards through said channel and outwardly between the blades above the tray level, said passages being positioned to be situated above the tray level when the valve is in its uppermost position.

References Cited in the file of this patent UNITED STATES PATENTS 1,057,576 Mussell Apr. 1, 1913 1,188,524 Worden June 27, 1916 =1,453,73-5 Twining May 1, 1923 2,061,830 Campbell Nov. 24, 1936 2,151,442 Roberts et a1 Mar. 21, 1939 2,640,677 Craven June 2, 1953 2,918,078 Cummings Dec. 22, 1959 3,055,646 Eld et a1 Sept. 25, 1962 3,080,155 Glitsch et a1 Mar. 5, 1963 FOREIGN PATENTS 721,247 Great Britain J an. 5, 1955 OTHER REFERENCES Petroleum Refiner, volume 39, No. 6, page 46, June 1960. 

1. A GAS-LIQUID CONTACTING APPARATUS COMPRISING: A CONTACTING TRAY ADAPTED TO BE MOUNTED HORIZONTALLY WITHIN A CONTACTING COLUMN TO RETAIN A BODY OF LIQUID THEREON AND HAVING A FLOW OPENING THERETHROUGH, AND A VALVE MOUNTED ON SAID TRAY FOR VERTICAL MOVEMENT TO CONTROL THE PASSAGE THROUGH SAID OPENING BY VERTICAL MOVEMENT DUE TO UPWARD GAS FLOW, SAID VALVE COMPRISING A VALVE PLATE SITUATED ABOVE THE TRAY ENGAGEABLE WITH THE UPPER TRAY SURFACE FOR SUPPORT WHEN THE VALVE IS IN ITS LOWEST POSITION, GUIDE MEANS EXTENDING VERTICALLY DOWNWARDLY THEREFROM NEAR THE EDGE OF SAID OPENING, THE LOWER PART OF SAID GUIDE MEANS PROVIDING STOPS ENGAGEABLE WITH THE UNDER SIDE OF THE TRAY TO LIMIT UPWARD MOVEMENT OF THE VALVE, SAID VALVE BEING ROTATABLE ABOUT THE VERTICAL CENTER LINE THEREOF, AND SPACED BLADES IN A PART OF THE VALVE WHICH IS SITUATED ABOVE SAID CONTACTING TRAY AT LEAST WHEN THE VALVE IS IN ITS UPPERMOST POSITION, SAID BLADE DEFINING GAS PASSAGES FROM WHICH GAS FLOWING IS DISPERSED DIRECTLY INTO SAID LIQUID, AT LEAST A PORTION OF THE BLADES INCLUDING MEANS WHICH ARE INCLINED FOR ROTATING THE VALVE COINCIDENTALLY WITH VERTICAL MOVEMENT THEREOF. 